Silicon semiconductor processing has evolved sophisticated operations for fabricating integrated circuits. An integrated circuit may include an interconnected array of active and passive elements, such as transistors, resistors, capacitors, and inductors, integrated with or deposited on a substrate by a series of compatible processes.
A bipolar junction transistor (BJT or bipolar transistor) is a type of transistor that relies on the contact of two types of semiconductor for its operation. BJTs may be used as amplifiers, switches, or in oscillators. BJTs may be found either as individual discrete components, or in large numbers as parts of integrated circuits.